Engine leakage meter



J. D. MORGAN ETALQ Aug. 31, 1943.

' ENGINE LEAKAGE METER Filed 001;. 29', 1940 JOHN D. MORGAN PERCY a. uzvrr-r INVENTOR5 ATTORNEY Patented Aug. 3l, 1943 ENGINE LEAKAGE METER John D. Morgan, South Orange, and Percy B. Levitt, Millbum, N. 1., assignors to Cities Service Oil Company, NewYor-k, N. Y., a corporation of Pennsylvania r Application October 29, 1940, Serial No. 363,256

3 Claims.

This invention relates to fluid flow measurement, and more particularly to improved apparatus adapted for measuring leakage of gas past the piston andvalves of an internal combustion.

engine cylinder.

The fluid flow measuring means the subject of the present invention are improve- 'ments on the apparatus and method of operating the same which is described in our U. S. Patent No. 2,003,949, patented June 4, 1935, for Gas engine leakage tester. The gas leakage tester of our aforesaid patent incorporates features of design which preclude the use of standard flttings and add considerably to the cost of fabrication and assembly, Prior to the development of the present invention there has been, so far as we know, no fluid flow measuring method and apparatus on the market which is adapted for furnishing accurate and easily understood measurements of the rate of gas leakage from an engine cylinder under a constant pressure head.

A primary object of the present invention,. is

therefore, to provide an improved means for making accurate measurements of the rate of gas leakage from a cylinder of an internal combustion engine.

Another object of the present invention is to provide a fluid leakage meter of such simple design that it can be rapidly and cheaply assembled from standard fittings.

Another object is to provide a fluid leakage meter of such simple calibration as to adaptit for operation by an unskilled operator.

With the above and other objects and features in view, the invention consists in the improved fluid leakage metering means hereinafter described and more particularly defined in the accompanying claims.

In the following description, the invention will be explained by reference to th attached drawing, in which: r

Fig. 1 is a view in side elevation, with parts in section, illustrating a preferred design of the fluid leakage meter; and

' 3 Fig. 2 is a view in front elevatiomwith the main part of the meter shown in longitudinal section.

which form this enlarged section of the bore has walls which are threaded throughout the length thereof. The

partition l8 consists of a centrally aperturedcylindrical member having an enlarged head with external threads which engage the internal threads at the enlarged end of the bore. The central aperture in the partition l8 provides a flow restricting orifice, normally of about /8" diameter, communicably connecting fluid inlet chamber l4 and fluid outlet chamber [8.

At the end of the housing opposite that which is threadably engagedby the partition iii, the threadedend of the bore engages external threads on a tubular connection 2| to a pressure operated In the drawing, l0 designates a tubular housing having a longitudinal cylindrical bore [2. The walls of the housing are threaded internally at each end of the bore, and the interior of the bore is divided into a fluid inlet chamber H and a fluid outlet chamber It by a removable partition it. In the drawing that end of the bore 12 in which outlet chamber It is located is shown to be of larger diameter than the rest of the bore, and

flow meter or gauge 22, preferably of the Bourdon tube type. A pair of oppositely disposed wall ports at the fluid inlet chamber end of the 110115? ing are threaded for engagement respectively by an externally threaded fluid inlet nipple 24 and by an externally threaded needle valve fitting 2B. Th needle valve 2! is so dimensioned and mounted in fitting 26 as to form an adjustable closure for the discharge end port in inlet nipple 24.

An externally threaded fluid outlet and adapter nipple 2B is shown as operatively mounted in the threaded outlet chamber end of the housing It). A pressure gauge 30 (Fig. l) is mounted with the front of its housing bolted to the back of gauge 22, and has a tubular connection 32 which is ported out at 34 into fluid outlet chamberlii. The gauge 30 is provided with an extra long pin ion shaft 36 for its indicating needle 38; shaft 36 extending forwardly through the lower part of the casing for the gauge 22 a distance suflicient to bring needle 38 in front of the indicating dial for gauge 22.

In using the leakage meter for measuring gas leakage past the piston and valves of a cylinder of a four-stroke cycle internal combustion engine, the piston in the cylinder under examination is locked in its top dead center position on compression stroke, at which point of the piston cycle both the intake and exhaust valves are.

closed. A spark plug is then removed from the wall of the cylinder combustion chamber, and the leakage meter is connected to the combustion chamber and cylinder by screwing adapter 28 into the spark plug socket. A source of compressed air under a pressure preferably in excess of lbs. per square inch, is then connected to the inlet nippl 24, and valve 21 is opened and its position adjusted to maintain the pressure inthe outlet chamber It at the downstream side of orifice 20 or the meter at a constant pressure of say 50 lbs. gauge. Needle 38 of the gauge 30 con- If there were no leakage from the enginevalvesand cylinder under test, the pressure in chamber H of the meter would equal the pres- 7 sure in chamber 16 of the meter, and needle 38 of gauge 30 would. be aligned with point "50 ofv its scale when needle 40 of gauge 22 aligns with the zero point on its scale, indicating 50 lbs.

I pressure in both the inlet and outlet chambers In other words, in order age and maintain a constant pressure of 50 lbs.

of the meter, or would indicate no leakage from the combustion chamber under test. There is always some gas leakage from the engine valves and cylinder at the test pressure employed, however, and this leakage from the engine valves and cylinder results in a differential pressure between the chambers I4 and iii of the meter.

to make up for the leakin the discharge chamber I6, valve 21 has to be adjusted to maintain a pressure in excess of 50 lbs. in chamber I4. The greater'the pressure difierential between these two gauge chambers, the greater is the rate of flow of air past orifice 20 of the meter required to make up gas leakage from the-engine combustion chamber and cylinder. The scale of gauge 22 is calibrated to measure the differential pressure directly in terms of rate of air bustion chamber in cubic feet per minute. For example, the leakage meter illustrated has an orifice 20 which is one inch in length and 4; inch in diameter, and is calibrated to deliver air at the rate of approximately 8 cubic feet per minute to the engine cylinder under a pressure differential of 10 lbs., corresponding to 60 lbs. pressure in chamber H, and 50 lbs. pressure in chamber 16. This rate increases to approximately 14 cubic feet per minute with air at 75 lbs. pressure in chamber l4, and 50 lbs. pressure in chamber I 6. Ordinarily an engine cylinder and valves of a combustion chamber having a leakage in excess of approximately 10 cubic feet per minutaat a constant test pressure of 50 lbs. per square inch, require attention to correct such condition.

Having thus described the invention, what is claimed as new-is: 1. A fluid leakage meter comprising atubular housing having a longitudinal cylindrical bore, a cylindrical partition member dimensioned for insertion within said bore to divide the bore into fluid inlet and outlet chambers, said member having a flow restriction orifice therein communicably connecting said chambers, a pair of oppositely disposed apertures in the wall of the inlet chamber, a pressure fluid supply tube fitted in one of said apertures, and a needle valve fltted in said other aperture in position for closing and delivered to the engine com-- ing for indicating a thereto under 2,328,289 5 will indicate delivery of air opening a port at the discharge end of the supply tube, a pressure operated flow gauge having a tubular connection fitted in the inlet chamber end of-the bore, a pressure fluid discharge nipple fitted in the discharge chamber end of the bore, and a pressure gauge having a tubular connection ported out in the discharge chamber, said gauges being mounted to incorporate a common indicating dial. i

2. A leakage meter for measuring the rate of gas leakage through the valves and around the piston in a cylinder associated with a combustion chamber of an internal combustion engine, which comprisesa housing having gas inlet and gas outlet chambers connected by a relatively long tubular gas passageway of relatively small diameter compared to that of said chambers adapted to create a pressure differential between said chambers when gas is flowing therethrough, a valve controlled inlet for admitting gas under pressure to said gas inlet chamber, a gas outlet connection for said gas outlet chamber adapted to be connected in a fluid-tight manner to said combustion chamber for the delivery 'of gas thereto under pressure, a pressure gage connected into the gas outlet chamber of said houssaid chamber, and a pressure responsive instrument connected. into the gas inlet chamber of said housing for indicating the gas leakage rate through said valves and said cylinder'of said combustion chamber. i i

3. A leakage meter gas leakage through for measuring the rate of the valves and around the piston in a cylinder associated with a combustion chamber ofan internal combustion engine, which comprises a housing having a longitudinal cylindrical bore divided into gas inlet and gas a partition containing a tubular gas passageway of approximately one inch said passageway connecting said chambers and being of relatively small diameter compared to that of said chambers and adapted to create a pressure differential between said chambers when gas is flowing therethrough,. a valve controlled inlet for admitting gas under pressure to said inlet chamber, a gas outlet connection for said gas outlet chamber adapted to be connected in a fluid-tight manner to said combustion chamber for the delivery of gas pressure, a pressure gage connected into the gas outlet chamber of said housing for indicating a predetermined pressure therein, a pressure responsive instrument connected into the gas inlet chamber of said housing for indicating the gas leakage rate through said valves and said cylinder of said combustion chamber when a predetermined pressure is maintained in said outlet chamber and said com bustion chamber.

JOHN D. MORGAN. PERCY B. LEVITT.

predetermined pressure in 

